Shock absorbing mechanism



Aug. 25, 1959 L. A. WILSON ETAL 2,900,331

SHOCK ABSORBING MECHANISM Filed Nov. 15, 1956 ENTORS LAWRE A.W|LSONBENJAMIN M. DURFEE HARRY J. TASHJIAN THEIR ATTORNEYS United StatesPatent SHOCK ABSORBING MECHANISM Lawrence A. Wilson, Apalachin, BenjaminM. Durfee, Binghamton, and Harry J. Tashjian, Endwell, N.Y., assignorsto International Business Machines Corporation, New York, N.Y., acorporation of New York Application November 15, 1956, Serial No.622,421

2 Claims. (Cl. 74-2165) The present invention relates generally to shockab sorbing mechanisms and more particularly to a mechanism for absorbingthe shock developedin a belt drive.

In machines such as, for example, IBM card feeding machines, highstarting and stopping torques cause breakage in the timing belts whichconnect the various operating parts. Therefore, for convenience, thepresent invention will be described in connection with an IBM cardfeeding machine, it being understood that the invention is not limitedthereto.'

The present invention provides generally a shock absorbing drivemechanism which will preventbreakage in the timing belt drives. Thedriven elements of the machine are divided into two groups: those inwhich no movement such as oscillation can be tolerated, and those inwhich some small oscillatory movement may be tolerated.

Accordingly, the driven elements of the machine in which no movement maybe tolerated must be connected directly to the driver clutch shaft by apositive drive means, and the elements of the machine in which somesmall oscillatory movement may be tolerated are connected to the driverclutch shaft through the shock absorbing mechanism of the presentinvention.

Generally, the present invention comprises two spacedapart idler pulleysbetween which a timing belt is passed to operably connect a power clutchshaft to one or more load shafts. The idler pulleys are yieldablymaintained in a predetermined position by one or more suitable resilientmeans such as, for example, coil springs which allow the pulleys toshift to absorb starting and stopping shock tensions developed in thebelt.

Therefore, one of the objects of the present invention is to provide amechanism for absorbing shock tensions developed in belt drives.

Another object of the present invention is to provide a means forcontrolling the tension in a belt drive.

The invention further resides in certain novel features of parts andfurther objects and advantages therein will become apparent to thoseskilled in the art to which it pertains from the following descriptionof the present preferred embodiment thereof described with respect tothe accompanying drawing in which the single figure illustrates thepreferred embodiment of the present invention.

Referring now to the single figure in the drawing, the operatingelements of a card feeding machine are illustrated as being divided intotwo groups: those elements 11 in which some movement or oscillation maybe tolerated, and those elements 12 in which no movement or oscillationmay be tolerated. The card feeding mechanism 12 is selected toillustrate that portion of a card feeding machine which must stopinstantly with the power clutch shaft and, therefore, is shown as beingdriven directly by means of a flexible belt 13 from a power clutch shaft14. Therefore, from the direct connection of the card feeding mechanism12 to the power clutch shaft 14 it may be seen that the card feedingmechanism 12 will stop at the instant that the power clutch shaft 14stops.

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The feed rollers 21, 22 and 23 are illustrated as the elements 11 of thecard feeding machine in which some movement or oscillation may betolerated. A flexible belt 24 with teeth 25 connects the two feedrollers 21 and 22 with the power clutch shaft 14. The connection of twofeed rollers 21 and 22 is shown for illustration purposes only.Obviously the flexible belt 24 may connect only one feed roller with thepower clutch shaft 14, or it may connect a plurality of feed rollers tothe power clutch shaft. Therefore, for descriptive purposes only, thisinvention will be described. in connection with the two feed rollers 21and 22.

A flexible belt 24 with teeth 25 drives the two feed rollers 21 and 22from a power clutch shaft 14. The flexible belt 24 is shown in operablerelationship with gears 27 and 28 which are secured to the shafts 18 and19, respectively, as are the feed rollers 21 and 22, respectively. Theflexible belt 24 passes between two idler pulleys 31 and 32 whichkeepthe belt 24 taut during operation. A gear 33 which is mounted on thepower clutch shaft 14 drives the flexible belt 24 to rotate the feedrollers 21 and 22.

a The two idler pulleys 31 and 32 are mounted on an elongated arm 34which is wedge-shaped, as shown in the drawing. The point 36 of thewedge is pivoted about an axis 37 on the base (not shown) of themachine. At the opposite end of the elongated arm .34 an integralextended portion 38 is formed.

An aperture 39 located in the extended portion 38 al lows a rod 41 to beextended therethrough. The rod 41 may be threaded into a base portion 42of the machine, or it may be mounted on the base 42 by any suitablemeans, as for example, by a nut 43 threaded on the end 44 of the rod 41.

A first spring 46 mounted about the rod 41 bears against the baseportion 42 at one end 47 and at the opposite end 48 against one side ofthe extended portion 38. A second spring 50, which is similar to spring46, bears at the end 53 against a nut 49 threaded onto the end 51 of rod41 and at the end 52 against the opposite side of the extended portion38 from the spring 46. Obviously, however, the two springs 46 and 50 maybe replaced by a single spring which may bear against the base portion42 at one end 47 and against the nut 49 at the end 53 with the extendedportion 38 being secured to the spring at a point approximately midwaybetween ends 47 and 48.

Another gear 55 may be mounted so that the movement of the two feedrollers 21 and 22 will cause movement in a further feed roller 23 in themachine. Additional rollers 56, 57 and 58 may be mounted to bear againstthe feed rollers 21, 22 and 23, respectively, in order to keep cards fedinto the machine in close contact with the feed rollers.

In operation, the power clutch shaft 14 with the power gear 33 mountedthereon starts by turning, for example, in a clockwise direction. Thefeed rollers 21 and 22 resist this turning due to their inertia and,therefore, excessive tension would be developed in the flexible belt 24.However, the elongated arm 34 will pivot about a pivot point 37 in aclockwise direction due to the pull by the flexible belt 24 against theidler pulley 31 and the extended portion 38 will compress spring 50 toabsorb the initial tension developed in the flexible belt 24. After themachine has started, the elongated member 34 will move back toward itsinitial position which position is illustrated in the drawing and willoscillate thereabout (approximately two oscillations of significantmagnitude) until it finally comes to rest. The flexible belt 24 is kepttaut during this cycle due to the relationship of the two idler pulleys31 and 32.

In stopping the machine, the power clutch shaft 14 stops in an instant.However, the feed rollers 21 a'nd22 will "*have a tendency to continueto rotate due to their inertia. The elongated arm 34 will then be pulled-in--a counterclockwise direction against spring 46 to absorb thetension developed in the flexible belt 24. After the feed rollers '21and '22 come to lrest, they will rotate in the opposite direction'andoscillate as the elongated arm 34 seeks its rest position. Thus, theshock, whichordinarily would belabsorbed in the flexible belt 24, willnew be absorbed in the springs 46 and 50 and belt breakage -from thiscause will be avoided. a

It may be readily seen that the present invention provides a shockabsorbing drive mechanism which will absorb iboth starting and stoppingshock on that part of the load which can tolerate oscillation, and 'atthe same time provide a home position, due to the spring arrangement,which allows a positive :timing relationship between the drive and thecard displacement.

"It will be understood that the embodiinent herein described is merelyillustrative of the invention and orieapplication thereof, and thatmodifications can be :made and it is capable of other applications.

We claim:

1. A shock absorbingdrive mechanism for driving at least one load shaftcomprising :apow'er shaft, an elongated idler armrotatably mounted atoneend, two spacedapart idler pulleys mounted adjacent each other on saididler arm ata distance from said rotatably mounted-end, flexible beltmeans mounted about said power shaft and said load shaft and passingbetween and engaging said two idler pulleys, an'extendedportion on saididler attached to the end near .said idler pulleys, {and a spring meansconnected to said extended portion to resiliently resist movement oftheidler arm fromapredetermined posi tion.

2. A shock absorbing drive mechanism for driving a plurality of loadshafts comprising a power shaft, a wedgeshaped idler arm rotatablymounted at one end, two spaced-apart idler pulleys mounted adjacent eachother on said idler ,arm at ;-a distance from said rotatably mountedend, flexible belt means mountedjabout said power shaft and {saidplurality of load shafts "and passing between and engaging said twoiidle'r pulleys, an extended portion on said- 'idler arin attached tothe end near said idler pulleys and "having "an"aperture'therethrough,rod means extending through said aperture in asaidextendcd portion, andspring means about said rod means bearing against each side of saidextended portion to resiliently resist movement thereof.

' Refiene's Gitedfin the fil'eof'tliis patent- UNITED STATES rATENTs5253118 Riker Atig.'28,1894 1,848,423 Jackson Y I Mar. 8, 1932 1,871268"Hildebrand r Aug. 9, 193 2 ass-3,248 Graham May 1-5, 19 51 lg-639523AitSli'GF-Hitih "M'ay'26, 195-3 FOREIGN PATENTS 101,500 Great Britain m*5, 1917

